JEROME TUBIANA is a researcher specializing in Chad, South Sudan, and Sudan.

The ongoing conflict in South Sudan is often seen as a power struggle between the “big men,” as the South Sudanese call their political and military leaders, namely President Salva Kiir and rebel leader Riek Machar. But intertwined in the politics at the top are the local “cattle-camp politics,” the intertribal tensions that existed long before the start of the civil war.

On the surface, the fighting in South Sudan began at the end of 2013 when Kiir’s camp accused his then vice president, Machar, of plotting a coup. The truth behind this allegation is unclear, although Machar never hid his presidential ambitions. Indeed, tensions within the new government were there from the day South Sudan gained independence from Sudan in 2011. The internal struggles were not obvious, though, so most outsiders did not predict that the new country would so quickly degenerate into interethnic violence between Kiir’s Dinka ethnic group and Machar’s Nuer.

The Dinka community is the largest ethnic group in South Sudan, and it dominated the Sudan People’s Liberation Movement (SPLM) and its armed wing (SPLA) since the 1983 rebellion against the government in Khartoum, which turned into a war that lasted over two decades and ended in the division of Sudan into Sudan and South Sudan. Machar, Kiir’s main rival, is a Nuer, which is the second-largest tribe in the country. Since the 1980s, Machar’s struggle, like those of many Nuer, was as much against the SPLA as it was against the Sudanese government.

The two groups’ leaders, fighters, and communities were never fully unified after they signed a peace agreement in 2005. In the wake of the turmoil in 2013, some of the government Dinka forces conducted targeted killings of Nuer residents in South Sudan’s capital city of Juba, and the cycle of enmity resumed, with Nuer members of the army taking up arms against the government and winning control of large swaths of the country inhabited by Nuer—in the states of Unity,